The present invention relates to an operation confirming method when checking an actual operation path of industrial machinery which is provided with a plurality of shafts driven by servo motors in compliance with operation programs, and a control device suited to embodiments of the above-described operation confirming method.
Generally, where a job (welding and cutting) is carried out by industrial machinery (for example, industrial robots, machining centers) having a plurality of shafts, operation programs are prepared in advance, and the industrial machinery is caused to execute operations as per instructions by reading operation instructions written in the programs.
FIG. 13 is a configurational view showing the construction of a control device for a prior art industrial machine. In the drawing, 1 denotes a control device for industrial machinery, and the control device 1 is composed of an operation instruction data storing portion 2, a shaft operation instruction preparing portion 3, and a servo controller unit 4. Also, 5 denotes a servo motor that drives an object industrial machine.
The operation instruction data storing portion 2 is a device that stores operation programs prepared in advance and reproduces the same. When executing the operation programs, instruction data are sequentially read from the operation instruction data storing portion 2 into the shaft operation instruction preparing portion 3. Instruction data are control points of an object industrial machine, that is, end-effecter attaching portions in the case of industrial robots, or a position and a speed at a point that is used as a tool attaching reference in the case of a machining center, wherein a position Pi (i=0 through Nxe2x88x921, N: Number of all actuating points) and a speed Vti (Operating speed of Pi through Pi+1) are sequentially read into the shaft operation instruction preparing portion 3.
In the shaft operation instruction preparing portion 3, the instruction data are converted to operation instructions (quantity of operation per unit time) xcfx89j (j=1, , , M: M indicates the number of shafts) for servo motors 5 for respective shafts.
The operation is called xe2x80x9cinverted conversionxe2x80x9d for general industrial machinery, and is called xe2x80x9cpulse distributionxe2x80x9d in an NC (Numerical Control) apparatus used for a machining center, etc. Respective shaft operation instructions xcfx89j that are prepared herein are transmitted to the servo controller unit 4, and the servo controller unit 4 controls a servo motor 5 so that respective shafts of the servo motor 5 operate as per instructions xcfx89j.
In industrial machinery having such a construction as described above, before executing an actual job (welding, cutting, etc.), it is necessary to check whether or not the operation programs are prepared as intended. That is, it is checked whether or not control points of the industrial machinery operate while drawing an intended path. At this time, if any part of the program is inadequate when the industrial machinery is actuated at a speed that is designated by the operation program (hereinafter, an actual operation instruction speed), not only may an actual workpiece and/or fixture be damaged, but also an operator may be subjected to danger. Therefore, it is general that the industrial machinery is not operated at an actual operation speed, but is operated at lower speed than the actual operation speed.
In order for the industrial machinery to be operated at a lower speed, as shown in FIG. 14, the actual operation instruction speed Vti that is read from the operation instruction data storing portion 2 is passed through a low speed instruction converting portion 6 before transmitting the same to the shaft operation instruction preparing portion 3. In the low speed instruction converting portion 6, the instruction speed is decreased to a ratio xcex1(0 less than xcex1 less than 1) that is designated in advance. That is, Via=Vti*xcex1 is transmitted to the shaft operation instruction preparing portion 3 as a new instruction speed.
However, the following problems exist where an operation check is carried out in this type of prior art control device. FIG. 15 is a view showing a comparison of operation paths to describe the problems in an operation confirming method for industrial machinery, which is embodied by a prior art control device. In the drawing, P0 is an initial position of the control point of industrial machinery. When an operation program is prepared, which brings about an inverted L-shaped channel in which the control point advances from Point P0 to Point P1 at a constant speed, and next advances from Point P1 to Point P2 at a constant speed, the operation path in an actual job not bypassing the low speed instruction converting portion greatly depicts an inward curve, skipping Point P1 as shown by C0. This phenomenon is called an xe2x80x9cinward short-cutxe2x80x9d resulting from a so-called servo delay. The faster the speed becomes, the larger the curve becomes. On the other hand, if the speed is made lower, bypassing the low speed instruction converting portion, the operation path depicts a small curve outside the operation path C0 as shown by C1. That is, there is a problem in that, when confirming operations at a low speed, the operation path cannot reproduce the actual operation path at an actual operation speed.
Therefore, it is an object of the present invention to provide an operation confirming method capable of making, in order to enhance an operation program correction efficiency, an operation path at an operation confirming time (teaching mode) as identical as possible to that of an actual job time (play mode); and a control device therefor.
In order to solve the above-described and other problems, an operation confirming method for industrial machinery, by which the operation path is confirmed by actuating industrial machinery provided with a plurality of shafts driven by a servo motor controlled by a servo controller unit at a lower speed than an actual operation speed, according to the first aspect of the invention, comprises the steps of inputting respective shaft operation instruction values xcfx89j based on the above-described actual operation speed into a simulator, which reproduces a servo control loop at an actual operation speed in the above-described industrial machinery, and instructing a quantity xcfx89sj/P, which is obtained by dividing an output xcfx89sj from the above-described simulator by an appointed positive real number P to the above-described servo controller unit N times (however, N is the maximum natural number not exceeding the above-described real number P) as respective shaft operation instruction values.
Also, an operation confirming method according to the second aspect of the invention comprises the steps of inputting a quantity xcfx89j/P, which is obtained by dividing respective shaft operation instruction values xcfx89j based on the above-described actual operation speed by an appointed positive real number P, into a simulator, which reproduces a servo control loop at an actual operation speed of the above-described industrial machinery, N times (however, N is the maximum natural number not exceeding the above-described real number P), and instructing an output xcfx89sij from the above-described simulator into the above-described servo controller unit as respective shaft operation instruction values.
In the operation confirming method according to the third aspect of the invention, where the above-described actual operation speed is smaller than an appointed value, a value of the above-described real number P is determined to be 1.0.
In addition, in the operation confirming method according to the fourth aspect of the invention, where respective shaft instruction values xcfx89sj from the above-described simulator are smaller than values determined shaft by shaft in advance, a value of the above-described real number P is determined to be 1.0.
In the operation confirming method according to the fifth aspect of the invention, where the above-described respective shaft operation instruction values xcfx89j are smaller than values determined in advance shaft by shaft, the value of the above-described real number P is determined to be 1.0.
An operation confirming method according to the sixth aspect of the invention comprises the steps of storing operation paths of the above-described industrial machinery by actuating the industrial machinery at an actual operation speed, that is, positions of the above-described industrial machinery, which are sampled at respective appointed sampling times, as a row of points consisting of n+1 (however, n is a natural number); converting the above-described operation paths to a row of points consisting of Nxc2x7(n+1) by interpolating a zone between respective adjacent points of the above-described row of points by dividing the zone by a natural number N set in advance; and sequentially instructing position instructions of respective shafts corresponding to the above-described row of points of Nxc2x7(n+1) to the above-described servo controller unit.
In the operation confirming method according to the seventh aspect of the invention, a status inference observer is connected to a servo controller unit of the above-described industrial machinery, and an operation path is inferred by the above-described status inference observer by actually actuating the above-described industrial machinery at an actual operation speed.
The operation confirming method according to the eighth aspect of the invention further comprises the steps of inputting a current instruction value that is applied to the above-described servo motor; connecting a mechanical simulator, which requests operations of the above-described industrial machinery, to the servo controller unit of the above-described industrial machinery; and preparing an operation path for the above-described industrial machinery to operate at an actual operation speed by the above-described mechanical simulator.
The operation confirming method according to the ninth aspect of the invention further comprises the steps of inputting a rotation angle instruction of a shaft, which is driven by the above-described servo motor, into the servo controller unit of the above-described industrial machinery; connecting a servo mechanical simulator, which requests an operation of the above-described industrial machinery; and preparing an operation path for the above-described industrial machinery to operate at an actual operation speed by the above-described servo mechanical simulator.
Further, a control device for industrial machinery, according to the tenth aspect of the invention, including an operation instruction data storing portion that stores and reproduces operation programs for industrial machinery provided with a plurality of shafts driven by servo motors; a shaft operation instruction preparing portion that prepares operation instructions of respective shafts of the above-described plurality of shafts upon receiving instructions of the above-described operation instruction data storing portion; and a servo controller unit that provides a drive current to the above-described servo motors upon receiving respective shaft operation instructions of the above-described shaft operation instruction preparing portion; wherein the same control device further comprises, between the above-described shaft operation instruction preparing portion and the servo controller unit, a simulator that reproduces a servo control loop at an actual operation speed of the above-described industrial machinery upon receiving the above-described respective shaft operation instructions; and a low speed instruction converting portion that divides an output xcfx89sj of the above-described simulator by an appointed positive real number P and instructs the same to the servo controller unit N times (however, N is the maximum natural number not exceeding the above-described real number P).
The control device according to the eleventh aspect of the invention further comprises, between the above-described shaft operation instruction preparing portion and the servo controller unit, a low speed instruction converting portion that outputs a value, which is obtained by dividing the above-described respective shaft operation instructions by an appointed positive real number P, N times (however, N is the maximum natural number not exceeding the above-described real number P), and a simulator that reproduces a servo control loop at an actual operation speed of the above-described industrial machinery upon receiving an output of the above-described low speed instruction converting portion.
The control device according to the twelfth aspect of the invention further comprises: a status inference observer that is connected to the above-described servo controller unit and infers positions of the above-described industrial machinery; an operation result storing portion that stores the positions of the above-described industrial machinery, which are inferred by the above-described status inference observer, at a fixed cycle, and stores the operation path of the above-described industrial machinery as a row of points consisting of n+1; and a low speed instruction converting portion that converts the above-described operation path to a row of points of Nxc2x7(n+1) by interpolating a zone between adjacent points of the above-described row of points stored by the above-described operation result storing portion by dividing the zone by a natural number N set in advance and sequentially instructs position instructions of the respective shafts corresponding to the above-described row of points of Nxc2x7(n+1) to the above-described servo controller unit.
The control device according to the thirteenth aspect of the invention further comprises: a mechanical simulator that is connected to the above-described servo controller unit and requests an operation of the above-described industrial machinery by inputting a current instruction value applied to the above-described servo motor; an operation result storing portion that stores positions of the above-described industrial machinery, which are inferred by the above-described mechanical simulator, at a fixed cycle, and stores an operation path of the above-described industrial machinery as a row of points of n+1; and a low speed instruction converting portion that converts the above-described operation path to a row of points of Nxc2x7(n+1) by interpolating a zone between adjacent points of the above-described row of points stored by the above-described operation result storing portion by dividing the zone by a natural number N set in advance and sequentially instructs position instructions of the respective shafts corresponding to the above-described row of points of Nxc2x7(n+1) to the above-described servo controller unit.
The control device according to the fourteenth aspect of the invention further comprises: a servo mechanical simulator that requests an operation of the above-described industrial machinery by inputting a rotation angle instruction of a shaft driven by the above-described servo motor; an operation result storing portion that stores positions of the above-described industrial machinery, which are inferred by the above-described servo mechanical simulator, at a fixed cycle, and stores an operation path of the above-described industrial machinery as a row of points of n+1; and a low speed instruction converting portion that converts the above-described operation path to a row of points of Nxc2x7(n+1) by interpolating a zone between adjacent points of the above-described row of points stored by the above-described operation result storing portion by dividing the zone by a natural number N set in advance and sequentially instructs position instructions of the respective shafts corresponding to the above-described row of points of Nxc2x7(n+1) to the above-described servo controller unit.